The　rheological　behavior　of　carboxylate　gemini　surfactant　O,O　＇-bis(sodium　2-tetradecylcarboxylate)-p-dibenzenediol　(referred　to　as　C-14　phi　C-2(14))　with　a　concentration　of　140　mmol.L-1　in　aqueous　solution　in　the　presence　of　100　mmol.L-1　NaBr　was　investigated　by　frequency　sweep　and　steady　rate　sweep　measurements.　The　solution　showed　the　characteristics　of　a　Maxwell　fluid　with　a　single　stress　relaxation　time　at　low　shear　frequencies.　Analysis　by　the　living　polymer　model　indicated　that　C-14　phi　C-2(14)　formed　long　(3.6-6.8　mu　m)　wormlike　micelles　at　25　degrees　C,　which　were　observed　by　cryo-transmission　electron　microscopy　(cryo-TEM).　The　micelles　were　entangled　with　each　other,　resulting　in　a　very　viscous　solution　(the　zero-shear　viscosity　was　as　high　as　1.10x10(4)　Pa.s)　that　looked　like　a　gel.　On　raising　the　temperature　to　70　degrees　C,　the　relative　viscosity　was　still　as　high　as　1.8x10(4),　which　is　very　rare　for　anionic　wormlike　micelle　systems.　The　flow　activation　energy　(Ea)　was　estimated　to　be　(141　+/-　5)　kJ.mol(-1).　The　size　distribution　of　C-14　phi　C-2(14)　was　determined　by　dynamic　light　scattering.　Large　aggregates　with　a　size　of　similar　to　100　nm　were　observed　at　low　concentrations　of　5-10　mmol　.　L-1.　These　large　aggregates　readily　transformed　into　rodlike　and　then　wormlike　micelles　as　the　surfactant　concentration　increased.